Mountain chicken frogs back in Montserrat

Thu, 10 May 2012

Scientists from the IUCN Member organisations are hoping that one of the world's largest frogs is singing songs of love on the tiny Caribbean island of Montserrat and not just singing in the rain. Mating calls would mean the so-called "mountain chicken" frogs are looking to breed and hopefully dodge extinction.

The Durrell Wildlife Conservation Trust, Zoological Society of London (London Zoo) and the North of England Zoological Society (Chester Zoo) – all IUCN Members – together with Parken Zoo in Sweden have helped to rescue the frogs and created a breeding programme that has resulted in dozens of offspring.

Described as "iconic", the "mountain chicken" frogs (Leptodactylus fallax) are one of the world's largest frog species, with females weighing over 900g. Sadly, they have declined by 80% in the wild and are now listed as Critically Endangered on the IUCN Red List of Threatened Species™.

The human pressures were compounded by the threat of the island's active volcano, which has rendered parts uninhabitable since erupting in 1995. The outlook for the frogs was described as "desperate" when researchers discovered the infectious disease Chytridiomycosis on the island in 2009. This fatal fungal disease, which penetrates the skin of many amphibian species causing lesions which prevent the animals from taking in oxygen, is affecting amphibians globally.

"We were entering a very difficult situation three years ago," says Andrew Terry, Field Programme Director with Durrell. "A species we knew well, that was already under pressure, was brought to the very edge of extinction."

With only two uninfected populations remaining, conservationists set out on an emergency rescue mission to airlift 50 of the frogs from the island. A dozen of the animals were then relocated to the UK and Sweden, where scientists were able to successfully breed the frogs in captivity.

Following a short trial last year, 33 healthy frogs were released onto the island in January 2012 and a field team has spent three months tracking their movements.

"Some of the frogs were calling in the forest in the first night," said Sarah-Louise Smith, project co-ordinator for the Durrell-led Mountain Chicken Recovery Programme. "Three months later the fact that we still have live frogs in the release site looking healthy and calling is a very encouraging sign. When we find the frogs we collect data such as location, swabs of the skin to test for the chytrid and any signs they might be breeding."

Although the team reported that some of the released frogs have succumbed to the disease, Ms Smith suggested that this was expected and could actually help scientists to better understand the problem.

"All the information we've collected was previously unknown for mountain chicken and will help us understand the processes that are going on so that we are able to make informed decisions on how to manage the species."

"We still have a long way to go with our research and there is still a lot about the chytrid that we do not know but there are many people, local and international, dedicated to the mountain chicken and working hard to make sure we are successful," said Ms Smith.